update REF recipe `recipe_ref_scatterplot.yml` to work with CMIP7 data

[hb326]

The recipe recipe_ref_scatterplot.yml needs to be updated to run with CMIP7 data. Additionally, some of the observational dataset used in the recipe need to be updated:

• update recipe to run with CMIP7 data
• exchange dataset ESACCI-CLOUD with CLARA-AVHRR
• exchange dataset CALIPSO-ICECLOUD v1 with CALIPSO-ICECLOUD v1
• exchange dataset GPCP v2.3 with GPCP v3.3
• exchange dataset CERES-EBAF v4.2 (ESMValTool version) with CERES-EBAF v4.2 (obs4MIPs version)

[bouweandela]

I'll upload the new datasets once there is a pull request with an updated recipe in ESMValTool.